| 摘要 |
PURPOSE:To reduce poor insulation generating ratio and improve productivity by using a carbonaceous material having a determined characteristic as a negative electrode material and specifying the ratio of the volume weighted average particle size of the carbonaceous material to the thickness of a separator. CONSTITUTION:As a negative electrode 2, a carbonaceous material having a face space in (002) face of 3.70Angstrom or more and a true density less than 1.70g/cm<3>, and not having a heat generating peak at 700 deg.C or more by differential thermal analysis in air flow is used, and as a positive electrode 1, a material containing lithium of a quantity corresponding to the charge and discharge capacity of 250mAh or more per gram of the negative electrode carbonaceous material is used. The ratio of the volume weighted average particle size DMV of the carbonaceous material to the thickness (t) of a separator is 0.04 to 0.07. Hence, the average particle size of the carbonaceous material is set smaller than the thickness of the separator 3, whereby, even if the average particles of the carbonaceous material are fallen from the negative electrode 2 and adhered onto the negative electrode 2 surface, the electric contact with the positive electrode 1 through the separator 3 can be prevented. Hence, poor insulation generating ratio can be reduce, and productivity can be improved. |
